linux-kernel - [PATCH v7 04/22] perf arm-spe: Refactor arm_spe_get

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Date:   Fri,  6 Nov 2020 09:41:18 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Andre Przywara <andre.przywara@....com>,
        Dave Martin <Dave.Martin@....com>,
        James Clark <james.clark@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Al Grant <Al.Grant@....com>, Wei Li <liwei391@...wei.com>,
        linux-kernel@...r.kernel.org
Cc:     Leo Yan <leo.yan@...aro.org>
Subject: [PATCH v7 04/22] perf arm-spe: Refactor arm_spe_get_events()

In function arm_spe_get_events(), the event packet's 'index' is assigned
as payload length, but the flow is not directive: it firstly gets the
packet length from the return value of arm_spe_get_payload(), the value
includes header length (1) and payload length:

  int ret = arm_spe_get_payload(buf, len, packet);

and then reduces header length from packet length, so finally get the
payload length:

  packet->index = ret - 1;

To simplify the code, this patch directly assigns payload length to
event packet's index; and at the end it calls arm_spe_get_payload() to
return the payload value.

Signed-off-by: Leo Yan <leo.yan@...aro.org>
Reviewed-by: Andre Przywara <andre.przywara@....com>
---
 tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
index 06b3eec4494e..f1b4cb008837 100644
--- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
+++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
@@ -136,8 +136,6 @@ static int arm_spe_get_timestamp(const unsigned char *buf, size_t len,
 static int arm_spe_get_events(const unsigned char *buf, size_t len,
 			      struct arm_spe_pkt *packet)
 {
-	int ret = arm_spe_get_payload(buf, len, packet);
-
 	packet->type = ARM_SPE_EVENTS;
 
 	/* we use index to identify Events with a less number of
@@ -145,9 +143,9 @@ static int arm_spe_get_events(const unsigned char *buf, size_t len,
 	 * LLC-REFILL, and REMOTE-ACCESS events are identified if
 	 * index > 1.
 	 */
-	packet->index = ret - 1;
+	packet->index = arm_spe_payload_len(buf[0]);
 
-	return ret;
+	return arm_spe_get_payload(buf, len, packet);
 }
 
 static int arm_spe_get_data_source(const unsigned char *buf, size_t len,
-- 
2.17.1